A contactor is an electrically controlled switch device used for switching an electric power or control circuit of an electrical load device. Such a contactor comprises a base and, thereon, an electromagnet apparatus and a contact system. The electromagnet apparatus is used to operate (open or close) a contact system of a contactor, wherein the contact system comprises a movable contact and a stationary contact. Such an electromagnet apparatus includes a fixed part with a magnet core and a coil, and a movable magnet part being connected to the movable contact and movable between a rest position and a working position. To control the contactor, an electrical circuit board is electrically connected to the coil for energizing or de-energizing the electromagnet apparatus. Such an electrical circuit board comprises input terminals for power supply and output terminals for providing electricity to the coil. This means that the output terminals have to be connected to input terminals of the coil by some kind of connecting means.
The working environment of such a contactor is usually bumpy. Cables are used to connect the coil and the electrical circuit board since the cables, by their property, are flexible and therefore are able to take care of all bumpy movements without affecting mechanical and electrical connection between the coil and the electric circuit board. This however needs a demanding mounting process, meaning that the mounting has to be carried out in two stages, first mounting one end of the cable to an output terminal of the electric circuit board and then mounting another end of the cable to an input terminal of the coil. Such a mounting process is costly in view of the cost of an electrical circuit board. Cable connections also make it difficult to replace a circuit board because the replacement involves a dismantling process of a cable and a mounting process of the cable.
A Chinese patent application with the publication number CN101017748 discloses a contactor comprising a winding arranged in a foundation seat unit, a cavity being provided for receiving a controlling circuit board, and the output terminals of the controlling circuit board being connected to the windings by means of connection cables.